The influence of liquid conductivity on pulsed discharge generated by a vertical falling liquid electrode device

A novel atmospheric gas–liquid discharge device has been designed in this study to generate discharge directly around the vertical falling liquid column. The device is made up of a quartz tube, an H.V. electrode attached to the outer wall of the quartz tube, and a vertical falling liquid column acting as the liquid ground electrode in the quartz tube`s internal center. An ICCD camera and a 2D axisymmetric numerical modeling are used to analyze the temporal-spatial evolution of the pulsed discharge around the liquid electrode. The results of the experiment and simulation indicate that the propagation and sustaining time of the discharge are strongly dependent on applied voltage and liquid electrode conductivity. It is found that there is no discharge observed around the liquid electrode with a conductivity of 0.05 mS cm −1 . As the conductivity of the liquid electrode increases, the electric field applied in the gas phase increases. When the conductivity is greater than 0.05 mS cm −1 , the discharge is initiated around the intermediate region of the liquid electrode, then develops upwards and downwards along the liquid electrode. The discharge sustaining time increases with the increase of the conductivity and applied voltage. When the liquid electrode is replaced by the stainless-steel electrode, it is discovered that the discharge sustaining time of the stainless-steel electrode is lower than that of the liquid electrode at the same applied voltage. Analysis suggests that the prolonged discharge sustaining time is caused by the gas capacitance that is increased by water vapor released from the liquid electrode. The simulation results indicate that the discharge around the liquid electrode is constrained to the cone-shaped distribution by the non-uniform electric field around the liquid electrode when the conductivity increases to 200 mS cm −1 .